import React, { Component, PureComponent } from 'react';

class Child extends PureComponent {
  render() {
    console.log('1') // 持续打印报警告
    return (
      <div> textInComponent </div>
    );
  }
}

export default class App extends Component {
  state = {
    count: 100
  }
  render() {
    return (
      <div> 
        <button onClick = { () => {
          this.setState({ count: this.state.count + 1 })
        }}>add</button>{ this.state.count }
        <Child />
      </div>
    );
  }
}
